Circuit breaker



Aug. 7, 1945. J. D. HILLIARD CIRCUIT BREAKEB Filed 0G13. .17, 1942 providing less arc in the pot and reducing the pressure.

The circuit breaker shown in Fig. 2 is a twobreak circuit breaker in which the cover 6 supports the bushings I9, which in turn support the conducting studs 20. Slidably mounted on the conducting studs 20 are pots 2l resiliently biased to a downward position by means of springs 22. The bridging member 25 carried by and movable with the operating rod 2l, supports a stop member 25 which functions to push the pot against the action of springs 22 to the position shown upon upward movement of the operating rod 24.

The movable contacts 29 are slidably mounted on guides 28 supported on members 21 conductively carried by the bridging member 25. 'I'he movable contacts 29 are biased upwardly by springs 3| and are electrically connected to the members 21 by means of pigtails 30. As the contacts are movable relative to the bridging member 25 and stop member 26 and are spring biased, a predetermined contact pressure is maintained between the movable contacts 29 and the stationary contacts formed by the ends of studs 20. Stops 29 on the studs 20 limit the downward movement of the pots 2|.

'I'he arc extinguishing action of this modification is similar to that of the circuit breaker shown in Fig. 1, and similar advantages are obtained from such action. However, the pressure relieving action afforded as in the embodiment of Fig. 1, by forcingof the pot 2| upward against the action of springs 22, is additionally found in the forcing of contact 29 downward against the bias of spring 3|. This action provides rapid extension of the are and rapid clearance of the pressure gases in the throat.

A modication of the contact structure shown in Fig. 2 is illustrated in Fig. 3. The moving contact Il is hollow and is slidably mounted in and guided by the conducting member 40 and the pot operating member I3. A spring 42 provides the desired contact pressure. The stop 44 becomes effective to transmit downward movement of the bridging member 25 to 'the movable contact Il. A plgtail (not shown) or other suitable means may `be utilized to conduct current from contact 4l to the member 40.

Arc extinguishing action similar to that of the embodiments of Figs. 1 and 2 is obtained in Fig. 3,

as the contact making and breaking is always in the throat or closely adjacent thereto. The point of contact can be varied by relative dimensoning and positioning of the stops t3 and I4. Thus the throat action is effective from the inception of arcing and the arc is drawn back into the pot, preventing forcing o! the oil out of the pot prior to the arc being in the throat.

Although but several embodiments of the invention have been illustrated and described. it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a `uid break circuit breaker, a pair of fixed contacts, a pair of cooperating movable contacts, a bridging member connecting said pairs of cooperating contacts in series, means for slidably supporting said movable contacts on said bridging member, pressure chambers each enclosing one of said fixed and one of said movable contacts and provided with an opening therein into which said fixed and said movable contacts may extend, means whereby said chambers are slidably supported relative to said first contacts, means comprising stops on said bridging member fortransinitting movementl thereof to said chamber, 'and means dependent upon the extent of said stops from said bridging member for positioning the make and break point of said contacts in said pressure chamber, in said opening or external to said chamber and to said open- 2. In a circuit breaker, a fixed contact, a chamber enclosing said fixed contact, insulating and arc extinguishing fluid surrounding said contact in said chamber, a throat opening in said chamber, a second Contact movable relative to said fixed contact and cooperable to make and break therewth,"an operating member for moving said second Contact relative to said chamber, means for supporting'said chamber for movement'relative to said fixed contact, and means operative vto stop said relative movement between said second contact and s'aid'chamber when said second Contact is in said throat opening.

3. In a circuit breaker,a'fixed contact, a chamber enclosing saidV fixed contact, insulating and arc extinguishing uid surrounding said. contact in said chamber, a throat opening in said chamber, a second contact movable relative to said fixed contact and cooperable to make and break therewith, an operating member supporting said second contact' for movement relative to said chamber and'for movement 4relative to said operating member, and means operative to stop said relative movement between said second contact and said chamber when'said second contact is in said throat opening.

4. In a circuit breaker, a xed contact, a chamber enclosingsaid fixed contact, insulating and arcextinguishing fluid surrounding said contact in said chamber,` a throat opening in said chamber, a second contact movable relative to said fixed contact and'coop'erable to make and break therewith, an operating member supporting said second contact for movement relative to said chamber and formovement relative to said operating member, and means operative to stop said relative movement betweensaid second contact and said chamber when said second contact is immediately adjacent said throat opening.

5. In a fluid break circuit breaker, a fixed contact, arcooperating'movable contact, a member for operating saidmovable contact, means for supporting said `movable contact on said operating member forrelative movement therebetween, a pressure` chamber enclosing said fixed contact `and supported for movement `relative thereto and JOHN D. "HILLIARD, 

